Focal Segmental Membranoproliferative Glomerulonephritis: A Histological Variant of Denys-Drash Syndrome.

Introduction: Denys-Drash Syndrome (DDS) consists of a triad of pseudohermaphroditism, Wilms'tumor and nephropathy. This condition may manifest as a complete triad or in an incomplete form; with either one or a combination of the above features. The characteristic glomerular abnormality in DDS is diffuse mesangial sclerosis (DMS).Case report: We report two cases of DDS with focal membranoproliferative glomerulonephritis (MPGN). Both of our cases were males with ambiguous genitalia. They had a similar heterozygous germline mutation in exon 9 of WT1, c.1180C>T, p.R394W; a known mutation hotspot for DDS. Case 1 had nephropathy at the age of 4 years and Case 2 at 2.5 years with different rates of progression to end-stage renal failure. Conclusion: Our findings, in combination with other reports, illustrate the clinicopathological heterogeneity of DDS. There are no universal recommendations for optimal management of patients with DDS due to the inability to accurately predict affected individuals' progress.

A four-point clinical criteria distinguishes immune thrombocytopenia from acute lymphoblastic leukaemia.

Immune thrombocytopenia is the most common diagnosis of isolated thrombocytopenia. The dilemma encountered by paediatricians is missing diagnosis of acute leukaemia in children with isolated thrombocytopenia. We demonstrated childhood ITP could be diagnosed using a four point clinical criteria without missing a diagnosis of acute leukaemia. Hence, bone marrow examination is not necessary in children with typical features compatible with ITP prior to steroid therapy. This can encourage paediatricians to choose steroid therapy, which is cheaper and non-blood product, as first line platelet elevating therapy in children with significant haemorrhage.

Frequent occurrence of gastric cancer in Asian kindreds with Li-Fraumeni syndrome.

Type of cancer and age of onset in individuals with inherited aberrations in the tumour suppressor gene TP53 are variable, possibly influenced by genetic modifiers and different environmental exposure. Since 2009, the modified Chompret criteria (MCC) have been used to identify individuals for TP53 mutation screening. Using the TP53 mutation database maintained by the International Agency for Research on Cancer (IARC), we investigated if the MCC, mainly developed for a Caucasian population, was also applicable in Asia. We identified several differences in Asian families compared with similar Caucasian cohorts, suggesting that identification and management of Li-Fraumeni syndrome in Asia do not completely mirror that of North America and Western Europe. Early gastric cancer (<40 years) may be considered a new addition to the MCC especially for Asian families.

Host genetic variants of ABCB1 and IL15 influence treatment outcome in paediatric acute lymphoblastic leukaemia.

BACKGROUND: Host germline variations and their potential prognostic importance is an emerging area of interest in paediatric ALL. METHODS: We investigated the associations between 20 germline variations and various clinical end points in 463 children with ALL. RESULTS: After adjusting for known prognostic factors, variants in two genes were found to be independently associated with poorer EFS: ABCB1 T/T at either 2677 (rs2032582) or 3435 (rs1045642) position (P=0.003) and IL15 67276493G/G (rs17015014; P=0.022). These variants showed a strong additive effect affecting outcome (P<0.001), whereby patients with both risk genotypes had the worst EFS (P=0.001), even after adjusting for MRD levels at the end of remission induction. The adverse effect of ABCB1 T/T genotypes was most pronounced in patients with favourable cytogenetics (P=0.011) while the IL15 67276493G/G genotype mainly affected patients without common chromosomal abnormalities (P=0.022). In both cytogenetic subgroups, increasing number of such risk genotypes still predicted worsening outcome (P<0.001 and=0.009, respectively). CONCLUSION: These results point to the prognostic importance of host genetic variants, although the specific mechanisms remain unclarified. Inclusion of ABCB1 and IL15 variants may help improve risk assignment strategies in paediatric ALL.

Griscelli syndrome.

We report a case of Griscelli Syndrome (GS). Our patient initially presented with a diagnosis of haemophagocytic lymphistiocytosis (HLH). Subsequent microscopic analysis of the patient's hair follicle revealed abnormal distribution of melanosomes in the shaft, which is a hallmark for GS. Analysis of RAB27A gene in this patient revealed a homozygous mutation in exon 6, c.550C>T, p.R184X . This nonsense mutation causes premature truncation of the protein resulting in a dysfunctional RAB27A. Recognition of GS allows appropriate institution of therapy namely chemotherapy for HLH and curative haemotopoeitic stem cell transplantation.

Childhood adrenocortical carcinoma as a sentinel cancer for detecting families with germline TP53 mutations.

Li-Fraumeni syndrome (LFS) is a highly penetrant, autosomal dominant disorder where affected individuals carry a 50% risk of developing cancer before 30 years of age. It is most commonly associated with mutations in the tumour suppressor gene, TP53. Adrenocortical carcinoma (ACC) is a very rare paediatric cancer, and up to 80% of affected children are found to carry germline TP53 mutations. Hence, we propose using childhood ACC incidence as selection criteria for referral for TP53 mutation testing, independent of familial cancer history. Under the auspices of the Malaysian Society of Paediatric Haematology-Oncology, four eligible children diagnosed with ACC over a 30-month study period were referred for mutation testing. Three had a germline TP53 mutation. Subsequent TP53 testing in relatives showed two inherited mutations and one de novo mutation. These findings strongly support paediatric ACC as a useful sentinel cancer for initiating a germline TP53/LFS detection programme, particularly in countries where the lack of structured oncogenetic practice precludes the identification of families with LFS features.

Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline.

OBJECTIVES: The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas. METHODS: Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction. RESULTS: DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued. CONCLUSION: DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data. KEY POINTS: Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.

A rare X-linked inherited mucocutaneous syndrome in two siblings.

We report on an 11 year-old boy with dyskeratosis congenita who presented with dystrophic nails, dysphagia, hyperpigmentation and oral leukoplakia. He had a brother who died 14 years earlier with similar presenting symptoms and aplastic anaemia. Genetic studies of our patient demonstrated the presence of a DKC1 mutation and confirmed our diagnosis. Further genetic screening revealed that his mother and one of his four sisters are heterozygous for the same mutation.

Spontaneous splenic rupture secondary to phaeyohyphomycosis and splenic abscesses.

Phaeohyphomycosis consists of a group of mycotic infections characterized by the presence of dematiaceous (dark walled) septate hyphae. Splenic abscess and spontaneous rupture is an infrequent complication in children with haematological malignancies and can be life threatening. To the best of our knowledge this is the first report of a case of splenic rupture following the development of multiple abscesses secondary to infestation by this rare fungal species.

Malignant myeloid transformation in a child with severe congenital neutropenia (Kostmann's syndrome).

We report a case of a child with severe congenital neutropenia (Kostmann's syndrome) who was treated with daily prophylactic subcutaneous granulocyte colony-stimulating factor (G-CSF) from the age of eight to sixteen years before being discontinued for poor haematological and clinical response. She did not have a HLA-matched sibling to enable bone marrow transplantation. She subsequently developed acute megakaryoblastic leukemia at the age of 17 years and succumbed during induction chemotherapy. The role of G-CSF in the pathogenesis of her malignant transformation to AML is complicated as this disorder has a propensity for myelodysplasia or AML as part of its natural history.

Secondary B-cell acute lymphoblastic leukemia following Wilms' tumor: clinical and in vitro chemosensitivity studies.

We report the clinical features and in vitro chemosensitivity assay findings of a 13-year-old girl who developed secondary B-cell acute lymphoblastic leukemia (ALL) 7 years after a diagnosis of Wilms' tumor. The patient was treated using the Berlin - Frankfurt - Muenster (BFM) ALL chemotherapy protocol with poor response to initial therapy before succumbing to sepsis. An in vitro chemosensitivity assay on her peripheral blood lymphoblasts was performed while she was undergoing induction therapy and showed a high level of resistance to drugs commonly used for ALL therapy, e.g. steroids, anthracyclines, vincristine and L-asparaginase. The mechanism of chemoresistance was not elicited, but was probably not related to P-glycoprotein (P-gp) over-expression. We believe that the in vitro chemosensitivity assay is a good indicator of cellular response to chemotherapy and may provide reliable information for the basis of the selection of drugs to be used for the treatment of similarly rare patients rather than relying on "standard" protocols.

Epidemiology and molecular characterization of nosocomially transmitted multidrug-resistant Klebsiella pneumoniae.

OBJECTIVES: To describe the epidemiology, antimicrobial susceptibility, genomic profiles, and control of a nosocomial outbreak of multidrug-resistant Klebsiella pneumoniae (MRKP) that occurred in the pediatric oncology unit of the University of Malaya Medical Centre in Kuala Lumpur. MATERIALS AND METHODS: A prospective epidemiologic and microbiologic study was conducted of MRKP isolated from the blood and wound of a boy with necrotizing fasciitis after a 7-day course of ceftazidime and amikacin. In the following 2 weeks, phenotypically similar MRKP were isolated from the blood cultures of four other patients and rectal swabs of another three patients and two liquid soap samples located in the same ward. RESULTS: Antimicrobial profiles demonstrated that all the isolates were resistant to ceftazidime, sensitive to imipenem and ciprofloxacin, and confirmed to be extended-spectrum beta-lactamase producers. Plasmids of varying molecular weights were present in all isolates. In eight of these isolates, which included four from blood, there were common large molecular weight plasmids ranging from 80 kb to 100 kb. Pulsed-field gel electrophoresis analysis using XbaI demonstrated six different DNA profiles, A to F. Profile A was shared by two blood culture isolates and were related by 91%. Profile B was found in one rectal swab isolate and one isolate from liquid soap and were related by 94%. Profile C was shared by one blood isolate and one liquid soap isolate and showed 100% relatedness. Profiles D, E, and F each were demonstrated by one blood isolate and two rectal swab isolates, respectively. These showed only 65% relatedness. CONCLUSIONS: The MRKP strains in this outbreak were not clonal in origin. The decline of the outbreak after 4 weeks was attributed to the reemphasis of standard infection control procedures and the implementation of a program that addressed sites of environmental contamination.

Ceftazidime-resistant Klebsiella pneumoniae bloodstream infection in children with febrile neutropenia.

OBJECTIVES: To evaluate prevalence of ceftazidime-resistant Klebsiella pneumoniae (CRKP) in the pediatric oncology unit of University Hospital, Kuala, Lumpur, and to identify differences between febrile neutropenic pediatric patients with CRKP and ceftazidime-sensitive K. pneumoniae (CSKP) bacteremia. MATERIALS AND METHODS: Febrile neutropenic patients treated between January 1996 and December 1997 at the pediatric oncology unit of University Hospital, Kuala Lumpur, were prospectively studied. Empirical antibiotic therapy consisted of ceftazidime and amikacin. Those who developed K. pneumoniae bacteremia were identified, and clinical features analyzed. Ceftazidime-resistance was documented via disk-diffusion testing. Production of extended-spectrum beta-lactamase (ESBL) was inferred on the basis of synergy between ceftazidime and amoxicillin-clavulanic acid. The different features between the two groups and variables associated with the development of CRKP bacteremia were analyzed using chi-square and t-tests and calculation of odds ratios. A multivariate analysis was used to identify independent factors for CRKP development. RESULTS: Ceftazidime-resistance was seen in 51.6% of all K. pneumoniae isolates, and all these isolates were inferred to be ESBL producers. All isolates were sensitive to imipenem. Susceptibility to gentamicin was 90.5%. The mean continuous hospital stay prior to the detection of bacteremia was 13.7 days overall, but significantly longer in the CRKP group (21.9 d) compared to the CSKP group (4.3 d) (P = 0.003). Children with CRKP were more likely to have received antibiotics in the 2 weeks prior to detection of bacteremia (87.5% of cases) than the CSKP group (20.0% of cases) (P = 0.0008). Sepsis-related mortality was higher in those with CRKP (50.0%) than in the CSKP group (13.3%) (P = 0.02). Patients who did not receive CRKP-directed antibiotics within 48 hours of admission were more likely to have a fatal outcome than those who did (P = 0.009). Logistic regression analysis identified use of third-generation cephalosporins 2 weeks prior to presentation and a hospital stay of 2 weeks or more as independent risk factors for development of CRKP. CONCLUSIONS: More than half of total K. pneumoniae isolated from blood cultures in the unit were ceftazidime-resistant. Children with febrile neutropenia with prolonged hospital stay and recent prior antibiotic exposure are at high risk of developing CRKP bacteremia. Mortality was significantly higher in this group. Early commencement of appropriate antibiotics (e.g., imipenem with or without gentamicin), according to susceptibility study results, may be beneficial in such circumstances.

Intraabdominal desmoplastic small round cell tumour in an 11-year-old boy.

A case of desmoplastic small round cell tumour (DSRCT) is presented. This aggressive and rare neoplasm predominantly affects males and is almost exclusively intraabdominal in location. It is unique in that neural, mesenchymal and epithelial markers are co-expressed. Despite multi-modal therapy, the prognosis is extremely poor. The present report details the clinical features and typical pathological findings of DSRCT in an 11-year-old boy, who succumbed to the disease 16 months after diagnosis despite multiple chemotherapeutic regimes.

Successful treatment of Candida albicans endocarditis in a child with leukemia--a case report and review of the literature.

Candida species is now being increasingly recognised as an important cause of endocarditis especially in immunocompromised patients. A case of Candida albicans endocarditis in a child with acute lymphoblastic leukemia (ALL) is reported. The child did not have a central venous catheter at any time. Treatment consisted of intravenous amphotericin B and fluconazole for 3 weeks followed by oral fluconazole for 2 weeks. No surgical resection was necessary. We highlight here the importance of echocardiography in the management of prolonged febrile neutropenia and discuss the dilemma of continuing chemotherapy in such patients.

Providing a cure for beta thalassaemia major.

The current treatment options for beta thalassaemia major patients include conservative treatment with blood cell transfusions and iron chelation or stem cell transplantation. Regular blood transfusions inevitably lead to multi-organ haemosiderosis and are attended by risks of blood-borne infections. Results from stem cell transplantation are good and suggest that this should be offered as first line therapy when a matched sibling donor is available because the patient is often cured and able to live a normal life. Of 38 Malaysian children who underwent bone marrow or cord blood transplantations using matched sibling donors, 29 (76%) are now cured.

Treating high risk childhood solid tumours with autologous peripheral blood stem cell transplantation--early experience in University Hospital, Kuala Lumpur.

Although survival rates for childhood cancers have improved steadily over the past two decades, the outcome for advanced stage solid tumours remains poor. Many of these tumours are chemosensitive but most chemotherapeutic regimens are limited by their haematological toxicities. Much attention is now focused on mega-dose chemotherapy followed by stem cell rescue in the treatment of disseminated neuroblastoma, rhabdomyosarcoma, germ cell tumour and brain tumours. There is a preferential shift towards peripheral blood stem cell transplantation instead of bone marrow transplantation because of its advantages of faster engraftment, decreased transfusion and antibiotic usage and shortened hospitalisation. This mode of therapy is dependent on technologies including peripheral blood stem cell harvesting, cell cryopreservation and thawing. These technologies were recently made available in Malaysia and we report our early experience.

Infantile myofibromatosis.

Infantile myofibromatosis (IMF) is a rare tumour with a wide spectrum of disease activity ranging from a solitary cutaneous nodule through to a multicentric form with widespread visceral involvement. It is characterised by its unique ability to spontaneously regress and has a typical histological appearance of actin-positive fibroblasts arranged in whorls or fascicles and vessels in a pericytomatous pattern. A male infant with multiple lesions involving the subcutaneous tissue and bone from birth is described and followed-up for two years. Treatment of IMF is dependent on the location of the tumour/s with surgery or chemotherapy reserved for rapidly progressive or symptomatic disease. However, due to the low rate of recurrence and the possibility of spontaneous tumoral regression, therapeutic abstention, as practised in our patient, is justified.

Second malignant neoplasms: an increasingly recognized complication of childhood cancer.

Second malignant neoplasms (SMN) are an increasingly recognized late complication seen in childhood cancer survivors. A total of 3 cases of SMN have been found in the Department of Paediatrics, University Hospital Kuala Lumpur after a 15-year experience of treating childhood malignancies. Two cases are described here. The first developed abdominal non-Hodgkin's lymphoma 3 years after undergoing an allogeneic bone marrow transplant for second relapse of acute lymphoblastic leukaemia, while the second child developed myeloid leukaemia two years after completing treatment for acute lymphoblastic leukaemia. Progress in the management of childhood cancer in Malaysia and the availability of bone marrow transplantation facilities have increased the number of childhood cancer survivors; leading to increased incidence of SMN.

Development of an algorithm of satellite markers for monitoring chimerism status in post-allogeneic haematopoietic stem cell transplantation patients.

INTRODUCTION: Analysis of variable number tandem repeats (VNTRs) by polymerase chain reaction (PCR) is a common method used to predict engraftment status in post-allogeneic haematopoeitic stem cell transplantation (HSCT) patients. Different populations have different copies of repeated DNA sequence and hence, different percentage of informativeness between patient and donor. METHODS: PCR amplification of four highly polymorphic VNTR markers (YNZ-22, D1S80, D1S111 and ApoB) was conducted on 60 patient-donor pairs. The informativeness of the markers was analysed using 3% agarose gel electrophoresis. RESULTS: We developed an algorithm for identification of informative VNTR markers in 60 post-allogeneic HSCT patients. YNZ-22 was the most informative (72%), followed by D1S80 (63%) and D1S111 (60%), while the least informative was ApoB (47%). The degree of informativeness achieved was 95%, which could discriminate 57 patient-donor pairs, when all four markers were combined. CONCLUSION: Since population genetic studies on VNTR loci are not well established in Southeast Asia, the present study is useful to determine reliable markers during the initial screening step of chimerism analysis. By following this algorithm, we are able to reduce time and cost of finding a suitable VNTR marker in our cohort.